`has_secure_password` is not invalid when assigning empty Strings.

Closes #9535.

With 692b3b6 the `password=` setter does no longer set blank passwords.
This triggered validation errors when assigning empty Strings to `password`
and `password_confirmation`.

This patch only sets the confirmation if it is not `blank?`.

1 files changed, 6 insertions, 0 deletions

diff --git a/activemodel/test/cases/secure_password_test.rb b/activemodel/test/cases/secure_password_test.rb
index 7783bb25d5..02cd3b8a93 100644
--- a/activemodel/test/cases/secure_password_test.rb
+++ b/activemodel/test/cases/secure_password_test.rb
@@ -88,4 +88,10 @@ class SecurePasswordTest < ActiveModel::TestCase
     @user.password = "secret"
     assert_equal BCrypt::Engine::MIN_COST, @user.password_digest.cost
   end
+
+  test "blank password_confirmation does not result in a confirmation error" do
+    @user.password = ""
+    @user.password_confirmation = ""
+    assert @user.valid?(:update), "user should be valid"
+  end
 end